Endoscopic bite block

ABSTRACT

According to a preferred embodiment of the present invention there is provided a bite block assembly adapted for capnography and oxygen delivery to a subject, the bite block assembly ( 50 ) including a first capnography passageway adapted for passage therethrough of exhaled breath from the subject to a capnograph and a second oxygen delivery passageway, separate from the first passageway, adapted for passage therethrough of oxygen from an oxygen source to the mouth of the subject.

REFERENCE TO RELATED APPLICATIONS

Reference is made to PCT Patent Application PCT/IL2004/000430, filed May20, 2004, entitled “ENDOSCOPIC BITE BLOCK”, the disclosure of which ishereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of bite blocks for endoscopicuse and specifically to endoscopic bite blocks suitable for use with gassampling or delivery cannulae.

BACKGROUND OF THE INVENTION

The following U.S. patents are believed to represent the current stateof the art: U.S. Pat. Nos. 5,174,284; 6,257,238; 6,422,240; 5,273,032and 5,513,634.

SUMMARY OF THE INVENTION

The present invention seeks to provide a new endoscopic bite block.

There is thus provided in accordance with a preferred embodiment of thepresent invention a bite block assembly adapted for capnography andoxygen delivery to a subject, the bite block assembly including a firstcapnography passageway adapted for passage therethrough of exhaledbreath from the subject to a capnograph, and a second oxygen deliverypassageway, separate from the first passageway, adapted for passagetherethrough of oxygen from an oxygen source to the mouth of thesubject.

Preferably the bite block assembly also includes a gas collectioncannula having formed therein the first capnography passageway.Additionally the gas collection cannula also includes an oxygen deliverycannula adapted to deliver oxygen from the oxygen source to the nostrilsof the subject. More preferably the oxygen delivery cannula is connectedto the oxygen source by a gas delivery tube.

Preferably the bite block assembly also includes a bite block havingformed therein the second oxygen delivery passageway.

More preferably the bite block assembly also includes a tube elementadapted to connect the oxygen delivery cannula to the second oxygendelivery passageway. Additionally, the tube element includes a branch ofthe gas delivery tube, and is adapted to connect to the second oxygendelivery passageway. Additionally the tube element is sealed by anormally closed valve. Preferably the normally closed valve includes aluer valve. Additionally a mating luer portion of the luer valve ismounted onto the oxygen delivery passageway.

Preferably the tube element is permanently mounted onto the bite blockand is adapted to connect to the gas delivery tube at a connection pointformed therein. Additionally the connection point is sealed by anormally closed valve. Preferably the normally closed valve includes aluer valve. More preferably a mating luer portion of the luer valve ismounted onto the tube element.

There is thus provided in accordance with another preferred embodimentof the present invention, a capnography system including a capnograph, abite block adapted to maintain the mouth of a subject open during amedical procedure, an exhaled breath sampling element which isconnectable to the capnograph and mountable onto the bite block, and anoral oxygen delivery passageway which is connectable to the bite blockfor delivering oxygen from an oxygen source to the mouth of the subject.

Preferably the exhaled breath-sampling element has at least one gascollection passageway, formed therein, the gas collection passagewaybeing configured to collect exhaled breath of the subject. Additionallythe at least one gas collection passageway includes a nasal gascollection passageway configured for collecting breath exhaled throughat least one nostril of the subject. Additionally or alternatively theat least one gas collection passageway includes an oral gas collectionpassageway configured for collecting breath exhaled through the mouth ofthe subject.

Preferably the capnography system also includes a nasal gas deliverypassageway for delivering oxygen from the oxygen source to at least onenostril of the subject. Additionally the nasal gas delivery passagewayis connected to the oxygen source by a gas delivery tube. Morepreferably the oral oxygen delivery passageway includes a tubular branchof the gas delivery tube.

Preferably the oral oxygen delivery passageway is sealed by a normallyclosed valve. Additionally the normally closed valve includes a luervalve. More preferably a mating luer portion of the luer valve ismounted onto the oral oxygen delivery passageway.

Preferably the oral oxygen delivery passageway is permanently mountedonto the bite block and is adapted to connect to the gas delivery tubeat a connection point formed therein. Additionally the connection pointis sealed by a normally closed valve. More preferably the normallyclosed valve includes a luer valve. Additionally a mating luer portionof the luer valve is mounted onto the oral oxygen delivery passageway.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIGS. 1A and 1B are simplified pictorial illustrations of an oral nasalsampling cannula forming part of an endoscopic bite block assembly,constructed and operative in accordance with a preferred embodiment ofthe present invention, in retracted and extended orientationsrespectively;

FIGS. 2A and 2B are front-view and rear-view simplified pictorialillustrations of an endoscopic bite block forming part of an endoscopicbite block assembly, constructed and operative in accordance with apreferred embodiment of the present invention;

FIG. 3 is a simplified sectional pictorial illustration of theendoscopic bite block of FIGS. 2A and 2B, taken along sections linesIII-III in FIG. 2B;

FIG. 4 is a simplified schematic illustration of the connection betweenthe oral nasal cannula of FIGS. 1A and 1B and the endoscopic bite blockof FIGS. 2A-3;

FIGS. 5A, 5B, 5C, 5D, 5E, 5F and 5G are pictorial illustrations ofvarious stages of typical use of the endoscopic bite block assembly ofFIGS. 1A-4;

FIGS. 6A and 6B are simplified pictorial illustrations of an oral nasalcannula forming part of an endoscopic bite block assembly, constructedand operative in accordance with another preferred embodiment of thepresent invention, in retracted and extended orientations respectively;

FIGS. 7A and 7B are front-view and rear-view simplified pictorialillustrations of an endoscopic bite block forming part of an endoscopicbite block assembly, constructed and operative in accordance withanother preferred embodiment of the present invention;

FIG. 8 is a simplified sectional pictorial illustration of theendoscopic bite block of FIGS. 7A and 7B, taken along sections linesVIII-VIII in FIG. 7B;

FIG. 9 is a simplified schematic illustration of the connection betweenthe oral nasal cannula of FIGS. 6A and 6B and the endoscopic bite blockof FIGS. 7A-8;

FIGS. 10A, 10B, 10C, 10D, 10C, 10F and 10G are pictorial illustrationsof various stages of typical use of the endoscopic bite block assemblyof FIGS. 5A-9;

FIGS. 11A and 11B are simplified pictorial illustrations of an oralnasal cannula forming part of an endoscopic bite block assembly,constructed and operative in accordance with yet another preferredembodiment of the present invention, in retracted and extendedorientations respectively;

FIGS. 12A and 12B are front-view and rear-view simplified pictorialillustrations of an endoscopic bite block forming part of an endoscopicbite block assembly, constructed and operative in accordance with yetanother preferred embodiment of the present invention;

FIG. 13 is a simplified sectional pictorial illustration of theendoscopic bite block of FIGS. 12A and 12B, taken along sections linesXIII-XIII in FIG. 12B;

FIG. 14 is a simplified schematic illustration of the connection betweenthe oral nasal cannula of FIGS. 11A and 11B and the endoscopic biteblock of FIGS. 12A-13; and

FIGS. 15A, 15B, 15C, 15D, 15E, 15F and 15G are pictorial illustrationsof various stages of typical use of the endoscopic bite block assemblyof FIGS. 11A-14.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A bite block is a device commonly used during upper gastro-intestinalendoscopic procedures to facilitate passage of anesophago-gastro-duodenoscopy (EGD) endoscope. The purpose of the biteblock is to allow the physician to perform the procedure without thesubject interfering by biting and damaging the endoscope tubing insertedvia his mouth, whether voluntarily or involuntarily.

The upper gastro-intestinal endoscopic procedure itself, together withthe use of a bite block, is often highly uncomfortable for the subjectand therefore it is very common for the subject to be sedated during theprocedure. Despite this, it is common for the subject to show oppositionto the procedure.

During upper gastro-intestinal endoscopy, and especially during longduration procedures performed under sedation, CO2 monitoring is oftenperformed using a separate nasal or oral/nasal cannula in conjunctionwith a bite block. Concomitant use of bite blocks and cannulae maynoticeably affect capnographic performance for a number of reasons,including inter alia misalignment between the cannula and the bite blockand inefficient oral sampling due to the space taken up by theendoscope. The present invention provides a solution that generally doesnot affect the capnographic performance.

Reference is now made to FIGS. 1A and 1B, which are simplified pictorialillustrations of an oral nasal sampling cannula forming part of anendoscopic bite block assembly, constructed and operative in accordancewith a preferred embodiment of the present invention, in retracted andextended orientations respectively.

FIGS. 1A and 1B show an oral nasal sampling cannula 10, which is adaptedfor collection of gases, such as carbon dioxide, exhaled by a subject,and for supplying oxygen to the subject.

The oral nasal sampling cannula 10 comprises a main body portion 12,having formed therein an exhaled breath collection bore 14 and an oxygendelivery bore 16. A pair of hollow nasal prongs 18, which are adaptedfor insertion into the nostrils of the subject, is integrally formedwith the main body portion 12. A hollow oral prong 22, which is formedwith a limiting rib 23 and a cut-away tip 24, is mounted onto a bottomsurface of main body portion 12. An oral breath directing element 26,which is preferably in the shape of a cut-away tube, is slidably mountedonto oral prong 22 by a mounting portion 28, and positioning of the oralbreath directing element 26 is limited by the limiting rib 23 of oralprong 22.

A channel formed in oral prong 22 is in fluid flow connection withchannels formed in nasal prongs 18, thereby forming a single junction32. Single junction 32 is in fluid flow communication with exhaledbreath collection bore 14, which in turn is in fluid flow communicationwith an exhaled breath collection tube 34, which is adapted to beconnected to a breath test analyzer or a capnograph (not shown), such asMicrocap® which is commercially available from Oridion Medical LTD. ofJerusalem, Israel.

Main body portion 12 is formed with oxygen delivery openings 36, whichare in fluid flow communication with oxygen delivery bore 16, which inturn is in fluid flow communication with an oxygen delivery tube 38.Alternatively, at least one nasal oxygen delivery prong, adapted forinsertion into the subject's nostril, may be used instead of oxygendelivery openings 36. Oxygen delivery tube 38 is adapted to be connectedto a source of oxygen (not shown).

Oxygen delivery tube 38 and exhaled breath collection tube 34 mayoptionally be placed around the ears of the subject, thereby stabilizingthe oral nasal sampling cannula 10 on the subject's face, such that anymovement of the subject will have a negligible effect on the placementof the oral nasal sampling cannula 10.

It is appreciated that oral breath directing element 26 may be in aretracted orientation as shown in FIG. 1A, or in an extended orientationas shown in FIG. 1B, thereby allowing the oral nasal sampling cannula 10to be suited to the facial dimensions of the subject, resulting in moreefficient collection of exhaled breath.

Reference is now made to FIGS. 2A and 2B, which are front-view andrear-view simplified pictorial illustrations of an endoscopic bite blockforming part of an endoscopic bite block assembly constructed andoperative in accordance with a preferred embodiment of the presentinvention and to FIG. 3, which is a simplified sectional pictorialillustration thereof.

FIGS. 2A, 2B and 3 show an endoscopic bite block 50, which is adapted tobe inserted into the mouth of a subject while the subject is sedated, toensure that the mouth of the subject is maintained open during theendoscopy process and that the subject does not interfere with theprocess by biting on the medical instruments used.

The endoscopic bite block 50 includes a main body portion 52, havingformed therein a central opening 54. A hollow tubular portion 56 extendsdistally from main body portion 52, such that the opening of tubularportion 56 is an extension of central opening 54. Central opening 54 isof a first height, indicated by H1 in FIG. 3, which is typically 16 to20 mm in bite blocks for adult use, which is the height required bymedical personnel for performing an endoscopy. In order to ensure thatduring breath sampling, oral prong 22 of oral nasal sampling cannula 10(FIGS. 1A and 1B) does not interfere with the space required by medicalpersonnel for performing the endoscopy procedure, the height of tubularportion 56 is greater than the height H1 of the central opening 54 asindicated by H2 in FIG. 3, and is typically 2 to 4 mm more than heightH1 (18 to 24 mm).

An outer surface 58 of tubular portion 56 is formed with top and bottomteeth engagement surfaces 60 and 62, such that top teeth engagementsurface 60 is relatively forward of bottom teeth engagement surface 62.This structure facilitates easy and accurate biting of the bite block 50by a subject, as it is suited to the jaw morphology of a closed humanmouth. Surface 58 is additionally formed with jaw engagement recesses64, which are formed forwardly of teeth engagement surfaces 60 and 62,respectively.

A top inner surface 70 of main body portion 52 is formed with alongitudinal groove 72 having a transverse surface 73, which is adaptedto accommodate oral prong 22 and oral breath directing element 26 of theoral nasal sampling cannula 10 (FIGS. 1A and 1B), as described with moredetail herein below with reference to FIG. 4.

A flexible barrier 76, preferably comprised of several flaps 78, isdisposed within central opening 54, thereby substantially closing offthe central opening and preventing dilution of exhaled breath by ambientair during sampling. An opening 80 is preferably maintained withinflexible barrier 76, thereby ensuring a small part of central opening 54remains open in order to enable the subject to inhale external air. Theflexible barrier 76 ensures that a majority of the subject's orallyexhaled breath will be directed toward oral prong 22 (FIGS. 1A and 1B)thereby ensuring accurate sampling of the subject's breath. Opening 80is preferably placed at a top part of central opening 54 near thecut-away tip 24 of oral prong 22 (FIGS. 1A and 1B), thereby directingexhaled breath toward the oral prong 22 as it is the only substantialexit.

The flaps 78 are preferably formed of a plastic material selected to beof suitable thickness to maintain their position when undisturbed, yetbend readily when pushed by an endoscope probe, and thus do not limitthe actions of the medical personnel performing the endoscopy. However,the flaps 78 preferably close back around the endoscope probe, thusmaintaining a substantially closed oral cavity volume and allowing mostof the exchange of gases to occur close to the opening 80 of theflexible barrier 76 which is close to the cut-away tip 24 of oral prong22 (FIGS. 1A and 1B) from which capnographic sampling can be performedaccurately. Additionally, the flaps 78 are preferably transparent, thusenabling medical personnel to see into the oral cavity during theendoscopy procedure.

Two attachment surfaces 82, each formed with a slit 84, extendhorizontally outwardly from main body portion 52. Slits 84 are adaptedto connect to a band which is placed around the subject's head and isused to maintain the endoscopic bite block 50 firmly in position duringthe endoscopy procedure. Preferably, slits 84 are located above ahorizontal centerline of main body portion 52, such that the connectedband will tend to exert a stronger pull to the top of the main bodyportion 52, thus assisting in overcoming the subject's tendency to tiltthe bite block 50 outward during the endoscopy procedure and inmaintaining the bite block 50 upright in the subject's mouth.

Reference is now made to FIG. 4, which is a simplified schematicillustration of the connection between the oral nasal sampling cannulaof FIGS. 1A and 1B and the endoscopic bite block of FIGS. 2A-3.

As seen in FIG. 4, oral prong 22 of oral nasal sampling cannula 10 isaccommodated within groove 72 of bite block 50, such that a bottomsurface of oral breath directing element 26 engages transverse surface73 of the groove 72. It is appreciated that transverse surface 73 islocated below an inner surface of tubular portion 56 in order to ensurethat air exhaled by the subject into tubular portion 56 will be directedtoward groove 72 and oral prong 22.

Reference is now made to FIGS. 5A, 5B, 5C, 5D, 5E, 5F and 5G, which arepictorial illustrations of various stages of typical use of theendoscopic bite block assembly of FIGS. 1A-4.

As seen in FIG. 5A, the nasal prongs 18 of the oral nasal samplingcannula 10 are placed in the subjects nostrils, preferably before thesubject is sedated. Preferably, the exhaled breath collection tube 34and the oxygen delivery tube 38 are placed around the subject's ears, inorder to ensure the stability of the oral nasal sampling cannula 10 onthe subject's face. As seen in the enlarged portion of FIG. 5A, at thisstage the oral breath-directing element 26 is in its retractedorientation, indicated by the length H3.

Turning to FIG. 5B, it is seen that the oral breath directing element 26is extended to accommodate the facial dimensions of the subject,revealing part of oral prong 22. Preferably, the oral breath-directingelement is moved down to a point in which a bottom end thereof is at theheight of the top of the bottom lip of the subject, its new length beingindicated by H4. This action is preferably preformed by medicalpersonnel, but may alternatively be performed by the subject himself, afamily member, or any other person.

FIG. 5C illustrates the insertion of bite block 50 into the mouth of thesubject, such that main body portion 52 engages the outer surface of thesubject's lips and the tubular portion 56 is inside the subject's mouth.A strap, indicated by reference numeral 90, is attached to slits 84 ofattachment surfaces 82 and is placed around the subject's head, therebysecuring the bite block 50 in place. This stage is preferably performedwhen the subject is sedated, but may alternatively be performed priorthereto.

As seen in the enlarged portion of FIG. 5C, the oral breath directingelement 26 and the oral prong 22 are accommodated in groove 72, suchthat a bottom surface of the oral breath directing element 26 engagestransverse surface 73 of groove 72. Additionally, if oral breathdirecting element 26 has been extended more than necessary for thefacial features of the subject, the transverse surface 73 pushes theoral breath-directing element 26 back, until it is optimally positioned.The lips of the subject, indicated by reference numeral 92 preferablyengage jaw engagement recesses 64, and the top and bottom teeth of thesubject, indicated by reference numerals 94 and 96 engage top and bottomteeth engagement surfaces 60 and 62, respectively.

Turning to FIG. 5D, it is seen that air exhaled orally by the subject,indicated by arrows, passes through the bore of tubular portion 56, andis directed toward oral breath directing element 26 and oral prong 22 bythe flaps 78 of flexible barrier 76. Air that is exhaled nasally by thesubject passes through nasal prongs 18.

FIG. 5E illustrates the sedated subject, having the nasal prongs 18 ofthe oral nasal sampling cannula 10 in his nostrils and the endoscopicbite block 50 placed in his mouth and strapped to his head. Preferably,once the subject is sedated, oxygen is supplied to the nose of thesubject via oxygen delivery openings 36 of oral nasal sampling cannula10, as indicated by arrows in the enlarged portion of FIG. 5E. Theoxygen is supplied to oxygen delivery openings 36 via oxygen deliverybore 16 (FIGS. 1A and 1B) and oxygen delivery tube 38.

Turning to FIG. 5F, it is seen that when the subject is sedated, hetends to move or slump his head, thereby moving oral nasal samplingcannula 10 relative to bite block 50, as indicated by angle α in theenlarged portion of FIG. 5F. The feature of the present invention whichprovides oral nasal sampling cannula 10 which is physically separatedfrom bite block 50 and the placement of oral breath directing element 26and oral prong 22 within groove 72, ensure that even when the subjectmoves or slumps his head, the oral prong 22 and nasal prongs 18 will bemaintained in their respective places, and accurate sampling willcontinue. Additionally, the placement of oral prong 22 within groove 72provides a counter force to force applied by the subject's tongue topush at least the top portion of the bite block 50 out of the subject'smouth, thus ensuring accurate placement of the bite block.

As seen in FIG. 5G, an endoscope probe 98 is inserted into the bore oftubular portion 56 of bite block 50, for performing an endoscopyprocedure. During the insertion of endoscope probe 98 and its presencein the subject's mouth and pharynx, flaps 78 of flexible barrier 76 bendslightly inward to allow the passage of the endoscope probe 98, as seenwith particular clarity in the enlarged portion of FIG. 5G. However, thecentral opening 54 of bite block 50 remains substantially closed byflaps 78, thereby separating the exhaled breath of the subject which isin the bore of tubular portion 56 from the ambient air.

Additionally, the sampling may continue during the presence of theendoscope probe 98 in the pharynx of the subject, as the tubular portion56 is of a slightly larger diameter than the central opening 54, therebyensuring that medical personnel have the space required for theendoscopy procedure and sampling can take place from the space definedby the difference between heights H2 and H1 (FIG. 3), as indicated byarrows in the enlarged portion of FIG. 5G.

It is appreciated that following the endoscopy, the bite block 50 may beremoved from the subject's mouth, preferably by medical personnel.However, the sampling of exhaled breath through nasal prongs 18 whichremain in the subject's nostrils and through oral prong 22 which remainsnear the subject's mouth, preferably continues until the subject hasawaken from the sedation. This is necessary because the subject's breathmust be monitored as long as the subject is sedated.

Reference is now made to FIGS. 6A and 6B, which are simplified pictorialillustrations of an oral nasal sampling cannula forming part of anendoscopic bite block assembly, constructed and operative in accordancewith another preferred embodiment of the present invention, in retractedand extended orientations respectively.

FIGS. 6A and 6B show an oral nasal sampling cannula 110, which isadapted for collection of gases, such as carbon dioxide, exhaled by asubject, and for supplying oxygen to the subject.

The oral nasal sampling cannula 110 comprises a main body portion 112,having formed therein an exhaled breath collection bore 114 and anoxygen delivery bore 116. A pair of hollow nasal prongs 118, which areadapted for insertion into the nostrils of the subject, is integrallyformed with the main body portion 112. A hollow oral prong 122, which isformed with a limiting rib 123 and a cut-away tip 124, is mounted onto abottom surface of main body portion 112. An oral breath directingelement 126, which is preferably in the shape of a cut-away tube, isslidably mounted onto oral prong 122 by a mounting portion 128, andpositioning of the oral breath directing element 126 is limited by thelimiting rib 123 of oral prong 122.

A channel formed in oral prong 122 is in fluid flow connection withchannels formed in nasal prongs 118, thereby forming a single junction132. Single junction 132 is in fluid flow communication with exhaledbreath collection bore 114, which in turn is in fluid flow communicationwith an exhaled breath collection tube 134, which is adapted to beconnected to a breath test analyzer or a capnograph (not shown), such asMicrocap® which is commercially available from Oridion Medical LTD. ofJerusalem, Israel.

Main body portion 112 is formed with oxygen delivery openings 136, whichare in fluid flow communication with oxygen delivery bore 116, which inturn is in fluid flow communication with an oxygen delivery tube 138.Alternatively, at least one nasal oxygen delivery prong, which isadapted to be inserted into the nostril of the subject, may be usedinstead of oxygen delivery openings 136. Oxygen delivery tube 138 ispreferably formed with a T-element 140, connecting the oxygen deliverytube 138 to an oral oxygen delivery tube 142. Oxygen delivery tube 138is adapted to be connected to a source of oxygen (not shown). Oraloxygen delivery tube 142 is preferably normally closed by a valveelement 144. Typically, the valve is a luer type valve.

Oxygen delivery tube 138 and exhaled breath collection tube 134 mayoptionally be placed around the ears of the subject, thereby stabilizingthe oral nasal sampling cannula 110 on the subject's face, such that anymovement of the subject will have negligible effect on the placement ofthe oral nasal sampling cannula 110.

It is appreciated that oral breath directing element 126 may be in aretracted orientation as shown in FIG. 6A, or in an extended orientationas shown in FIG. 6B, thereby allowing the oral nasal sampling cannula110 to be suited to the facial dimensions of the subject, resulting inmore efficient collection of exhaled breath.

Reference is now made to FIGS. 7A and 7B, which are front-view andrear-view simplified pictorial illustrations of an endoscopic bite blockforming part of an endoscopic bite block assembly constructed andoperative in accordance with a preferred embodiment of the presentinvention and to FIG. 8, which is a simplified sectional pictorialillustration thereof.

FIGS. 7A, 7B and 8 show an endoscopic bite block 150, which is adaptedto be inserted into the mouth of a subject while the subject is sedated,to ensure that the mouth of the subject is maintained open during theendoscopy process and that the subject does not interfere with theprocess by biting on the medical instruments used.

The endoscopic bite block 150 includes a main body portion 152, havingformed therein a central opening 154. A hollow tubular portion 156extends distally from main body portion 152, such that the opening oftubular portion 156 is an extension of central opening 154. Centralopening 154 is of a first height, indicated by H1 in FIG. 8, which istypically 16 to 20 mm in bite blocks for adult use, which is the heightrequired by medical personnel for performing an endoscopy. In order toensure that during breath sampling, oral prong 122 of oral nasalsampling cannula 110 (FIGS. 6A and 6B) does not interfere with the spacerequired by medical personnel for performing the endoscopy procedure,the height of tubular portion 156 is greater than the height H1 ofcentral opening 154 as indicated by H2 in FIG. 8, and is typically 2 to4 mm more than height H1 (18 to 24 mm).

An outer surface 158 of tubular portion 156 is formed with top andbottom teeth engagement surfaces 160 and 162, such that top teethengagement surface 160 is relatively forward of bottom teeth engagementsurface 162. This structure facilitates easy and accurate biting of thebite block 150 by a subject, as it is suited to the jaw morphology of aclosed human mouth. Surface 158 is additionally formed with jawengagement recesses 164, which are formed forwardly of teeth engagementsurfaces 160 and 162, respectively.

A top inner surface 170 of main body portion 152 is formed with alongitudinal groove 172 having a transverse surface 173, which isadapted to accommodate oral prong 122 and oral breath directing element126 of the oral nasal sampling cannula 110 (FIGS. 6A and 6B), asdescribed with more detail hereinbelow with reference to FIG. 9.

A tubular portion 174 is formed on a side of outer surface 158 oftubular portion 156. Tubular portion 174 is adapted to threadably engageoral oxygen delivery tube 142 (FIGS. 6A and 6B), thereby opening valve144 to the passage of gases and thus supplying oxygen directly to theoral cavity of the subject. Preferably, tubular portion 174 includes aluer portion corresponding to luer valve element 144. It is appreciatedthat tubular portion 174 is formed on outer surface 158 of tubularportion 156, in order to ensure that the oral oxygen delivery does notinterfere with the procedure performed by the medical personnel and sothat the oxygen flow does not directly interfere with the CO2 sampling.

A flexible barrier 176, preferably comprised of several flaps 178, isdisposed within central opening 154, thereby substantially closing offthe central opening and preventing dilution of exhaled breath by ambientair during sampling. An opening 180 is preferably maintained withinflexible barrier 176, thereby ensuring a small part of central opening154 to remain open in order to enable the subject to inhale externalair. The flexible barrier 176 ensures that a majority of the subject'sorally exhaled breath will be directed toward oral prong 122 (FIGS. 6Aand 6B) thereby ensuring accurate sampling of the subject's breath.Opening 180 is preferably placed at a top part of central opening 154near the cut-away tip 124 of oral prong 122 (FIGS. 6A and 6B), therebydirecting exhaled breath toward the oral prong 122 as it is the onlysubstantial exit.

The flaps 178 are preferably formed of a plastic material selected to beof suitable thickness to maintain their position when undisturbed, yetbend readily when pushed by an endoscope probe, and thus do not limitthe actions of the medical personnel performing the endoscopy. However,the flaps 178 preferably close back around the endoscope probe, thusmaintaining a substantially closed oral cavity volume, and allowing mostof the exchange of gases to occur close to the opening 180 of theflexible barrier 176, which opening is close to the cut-away tip 124 oforal prong 122 from which capnographic sampling can be performedaccurately. Additionally, the flaps 178 are preferably transparent, thusenabling medical personnel to see into the oral cavity during theendoscopy procedure.

Two attachment surfaces 182, each formed with a slit 184, extendhorizontally outwardly from main body portion 152. Slits 184 are adaptedto connect to a band which is place around the subject's head and isused to maintain the endoscopic bite block 150 firmly in position duringthe endoscopy procedure. Preferably, slits 184 are located above ahorizontal centerline of main body portion 152, such that the connectedband will tend to exert a stronger pull to the top of the main bodyportion 152, thus assisting in overcoming the subject's tendency to tiltthe bite block 150 outward during the endoscopy procedure and inmaintaining the bite block 150 upright in the subject's mouth.

Reference is now made to FIG. 9, which is a simplified schematicillustration of the connection between the oral nasal sampling cannulaof FIGS. 6A and 6B and the endoscopic bite block of FIGS. 7A-8.

As seen in FIG. 9, oral prong 122 of oral nasal sampling cannula 110 isaccommodated within groove 172 of bite block 150, such that a bottomsurface of oral breath directing element 126 engages transverse surface173 of the groove 172. It is appreciated that transverse surface 173 islocated below an inner surface of tubular portion 156 in order to ensurethat air exhaled by the subject into tubular portion 156 will bedirected toward groove 172 and oral prong 122.

Additionally, valve 144 (FIGS. 6A and 6B) of oral oxygen delivery tube142 is accommodated in tubular portion 174 of endoscopic bite block 150,thereby opening the valve element and forming a fluid flow engagementbetween oxygen delivery tube 138 and tubular portion 174 of endoscopicbite block 150, which is in fluid flow engagement with the oral cavityof the subject.

Reference is now made to FIGS. 10A, 10B, 10C, 10D, 10E, 10F and 10G,which are pictorial illustrations of various stages of typical use ofthe endoscopic bite block assembly of FIGS. 6A-9.

As seen in FIG. 10A, the nasal prongs 118 of the oral nasal samplingcannula 110 are placed in the subjects nostrils, preferably before thesubject is sedated. Preferably, the exhaled breath collection tube 134and the oxygen delivery tube 138 are placed around the subject's ears,in order to ensure the stability of the oral nasal sampling cannula 110on the subject's face. As seen in the enlarged portion of FIG. 10A, atthis stage the oral breath-directing element 126 is in its retractedorientation, indicated by the length H3. At this stage, oral oxygendelivery tube 142 is not connected to the bite block 150 (FIGS. 7A-8).

Turning to FIG. 10B, it is seen that the oral breath directing element126 is extended to accommodate the facial dimensions of the subject,revealing part of oral prong 122. Preferably, the oral breath-directingelement is moved down to a point in which a bottom end thereof is at theheight of the top of the bottom lip of the subject, its new length beingindicated by H4. This action is preferably preformed by medicalpersonnel, but may alternatively be performed by the subject himself, afamily member, or any other person.

FIG. 10C illustrates the insertion of bite block 150 into the mouth ofthe subject, such that main body portion 152 engages the outer surfaceof the subject's lips and the tubular portion 156 (FIGS. 7A-8) is insidethe subject's mouth. Additionally, valve 144 of oral oxygen deliverytube 142 is inserted, preferably by medical personnel, into tubularportion 174 of endoscopic bite block 150, as indicated by an arrow inthe enlarged portion of FIG. 10C, thereby opening the valve and allowingpassage of fluids from the oral oxygen delivery tube 142 into the oralcavity or the subject.

A strap, indicated by reference numeral 190, is attached to slits 184 ofattachment surfaces 182 and is placed around the subject's head, therebysecuring the bite block 150 in place. This stage is preferably performedwhen the subject is sedated, but may alternatively be performed priorthereto.

Turning to FIG. 10D, it is seen that air exhaled orally by the subject,indicated by arrows, passes through the bore of tubular portion 156, andis directed toward oral breath directing element 126 and oral prong 122by the flaps 178 of flexible barrier 176. Air that is exhaled nasally bythe subject passes through nasal prongs 118.

FIG. 10D illustrates the oral breath directing element 126 and the oralprong 122 being accommodated in groove 172, such that a bottom surfaceof the oral breath directing element 126 engages transverse surface 173of groove 172. Additionally, if oral breath directing element 126 hasbeen extended more than necessary for the facial features of thesubject, the transverse surface 173 pushes the oral breath-directingelement 126 back until it is optimally positioned. The lips of thesubject, indicated by reference numeral 192 preferably engage jawengagement recesses 164, and the top and bottom teeth of the subject,indicated by reference numerals 194 and 196 engage top and bottom teethengagement surfaces 160 and 162, respectively.

FIG. 10E illustrates the sedated subject, having the nasal prongs 118 ofthe oral nasal sampling cannula 110 in his nostrils and the endoscopicbite block 150 placed in his mouth and strapped to his head. Preferably,once the subject is sedated, oxygen is supplied to the nose of thesubject via oxygen delivery openings 136 of oral nasal sampling cannula110, and to the mouth of the subject via oral oxygen delivery tube 142and tubular portion 174, as indicated by arrows. The oxygen is suppliedto the oxygen delivery openings 136 via oxygen delivery bore 116 (FIGS.6A and 6B) and to oral oxygen delivery tube 142 via oxygen delivery tube138 and T-element 140.

Turning to FIG. 10F, it is seen that when the subject is sedated, hetends to move or slump his head, thereby moving oral nasal samplingcannula 110 relative to bite block 150, as indicated by angle α in theenlarged portion of FIG. 10F. The feature of the present invention whichprovides oral nasal sampling cannula 110 which is physically separatedfrom bite block 150 and the placement of oral breath directing element126 and oral prong 122 within groove 172, ensure that even when thesubject moves or slumps his head, the oral prong 122 and nasal prongs118 will be maintained in their respective places, and accurate samplingwill continue. Additionally, the placement of oral prong 122 withingroove 172 provides a counter force to force applied by the subject'stongue to push at least the top portion of the bite block 150 out of thesubject's mouth, thus ensuring accurate placement of the bite block.

As seen in FIG. 10G, an endoscope probe 198 is inserted into the bore oftubular portion 156 of bite block 150, for performing the endoscopyprocedure. During the insertion of endoscope probe 198 and its presencein the subject's mouth and pharynx, flaps 178 of flexible barrier 176bend slightly inward to allow the passage of the endoscope probe 198, asseen with particular clarity in the enlarged portion of FIG. 10G.However, the central opening 154 of bite block 150 remains substantiallyclosed by flaps 178, thereby separating the exhaled breath of thesubject which is in bore of tubular portion 156 from the ambient air.

Additionally, the sampling may continue during the presence of theendoscope probe 198 in the pharynx of the subject, as the tubularportion 156 is of a slightly larger diameter than the central opening154, thereby ensuring that medical personnel have the space defined bythe difference between heights H2 and H1 (FIG. 8), as indicated byarrows in the enlarged portion of FIG. 10G.

It is appreciated that following the endoscopy, the bite block 150 maybe removed from the subject's mouth, preferably by medical personnel.Prior to this stage, the valve 144 of oral oxygen delivery tube 142 isremoved from tubular portion 174 thereby closing the valve and thusfully decoupling the oral nasal sampling cannula 110 from the endoscopicbite block 150. However, the sampling of exhaled breath through nasalprongs 118 which remain in the subject's nostrils and through oral prong122 which remains near the subject's mouth, preferably continues untilthe subject has awaken from the sedation. This is necessary because thesubject's breath must be monitored as long as the subject is sedated.

Reference is now made to FIGS. 11A and 11B, which are simplifiedpictorial illustrations of an oral nasal sampling cannula forming partof an endoscopic bite block assembly, constructed and operative inaccordance with yet another preferred embodiment of the presentinvention, in retracted and extended orientations respectively.

FIGS. 11A and 11B show an oral nasal sampling cannula 210, which isadapted for collection of gases, such as carbon dioxide, exhaled by asubject, and for supplying oxygen to the subject.

The oral nasal sampling cannula 210 comprises a main body portion 212,having formed therein an exhaled breath collection bore 214 and anoxygen delivery bore 216. A pair of hollow nasal prongs 218, which areadapted for insertion into the nostrils of the subject, is integrallyformed with the main body portion 212. A hollow oral prong 222, which isformed with a limiting rib 223 and a cut-away tip 224, is mounted onto abottom surface of main body portion 212. An oral breath directingelement 226, which is preferably in the shape of a cut-away tube, isslidably mounted onto oral prong 222 by a mounting portion 228, andpositioning of the oral breath directing element 226 is limited by thelimiting rib 223 of oral prong 222.

A channel formed in oral prong 222 is in fluid flow connection withchannels formed in nasal prongs 218, thereby forming a single junction232. Single junction 232 is in fluid flow communication with exhaledbreath collection bore 214, which in turn is in fluid flow communicationwith an exhaled breath collection tube 234, which is adapted to beconnected to a breath test analyzer or a capnograph (not shown), such asMicrocap® which is commercially available from Oridion Medical LTD. ofJerusalem, Israel.

Main body portion 212 is formed with oxygen delivery openings 236, whichare in fluid flow communication with oxygen delivery bore 216, which inturn is in fluid flow communication with an oxygen delivery tube 238.Alternatively, at least one nasal oxygen delivery prong, adapted forinsertion into the subject's nostril, may be used instead of oxygendelivery openings 236. Oxygen delivery tube 238 is preferably formedwith a T-element 240, preferably terminating at an end thereof in anormally closed valve element 244, which is preferably a luer valve.Oxygen delivery tube 238 is adapted to be connected to a source ofoxygen (not shown).

Oxygen delivery tube 238 and exhaled breath collection tube 234 mayoptionally be placed around the ears of the subject, thereby stabilizingthe oral nasal sampling cannula 210 on the subject's face, such that anymovement of the subject will have negligible effect on the placement ofthe oral nasal sampling cannula 210.

It is appreciated that oral breath directing element 226 may be in aretracted orientation as shown in FIG. 11A, or in an extendedorientation as shown in FIG. 11B, thereby allowing the oral nasalsampling cannula 210 to be suited to the facial dimensions of thesubject, resulting in more efficient collection of exhaled breath.

Reference is now made to FIGS. 12A and 12B, which are front-view andrear-view simplified pictorial illustrations of an endoscopic bite blockforming part of an endoscopic bite block assembly constructed andoperative in accordance with yet another preferred embodiment of thepresent invention and to FIG. 13, which is a simplified sectionalpictorial illustration thereof.

FIGS. 12A, 12B and 13 show an endoscopic bite block 250, which isadapted to be inserted into the mouth of a subject while the subject issedated, to ensure that the mouth of the subject is maintained openduring the endoscopy process, and that the subject does not interferewith the process by biting on medical instruments used.

The endoscopic bite block 250 includes a main body portion 252, havingformed therein a central opening 254. A hollow tubular portion 256extends distally from main body portion 252, such that the opening oftubular portion 256 is an extension of central opening 254. Centralopening 254 is of a first height, indicated by H1 in FIG. 13, which istypically 16 to 20 mm in bite blocks for adult use, which is the heightrequired by medical personnel for performing an endoscopy. In order toensure that during breath sampling, oral prong 222 of oral nasalsampling cannula 210 (FIGS. 11A and 11B) does not interfere with thespace required by medical personnel for performing the endoscopyprocedure, the height of tubular portion 256 is greater than the heightH1 of central opening 254 as indicated by H2 in FIG. 13, and istypically 2 to 4 mm more than height H1 (18 to 24 mm).

An outer surface 258 of tubular portion 256 is formed with top andbottom teeth engagement surfaces 260 and 262, such that top teethengagement surface 260 is relatively forward of bottom teeth engagementsurface 262. This structure facilitates easy and accurate biting of thebite block 250 by a subject, as it is suited to the jaw morphology of aclosed human mouth. Surface 258 is additionally formed with jawengagement recesses 264, which are formed forwardly of teeth engagementsurfaces 260 and 262, respectively.

A top inner surface 270 of main body portion 252 is formed with alongitudinal groove 272 having a transverse surface 273, which isadapted to accommodate oral prong 222 and oral breath directing element226 of the oral nasal sampling cannula 210 (FIGS. 12A and 12B), asdescribed with more detail hereinbelow with reference to FIG. 14.

A tubular portion 274 is formed on a side of outer surface 258 oftubular portion 256. Extending out of tubular portion 274 is an oraloxygen delivery tube 275 including a tip 276, which is adapted to engagevalve 244 (FIGS. 11A and 11B), thereby supplying oxygen directly to theoral cavity of the subject. Preferably, tip 276 comprises a luercorresponding to luer valve 244. It is appreciated that tubular portion274 is formed on outer surface 258 of tubular portion 256, in order toensure that the oral oxygen delivery does not interfere with theprocedure performed by the medical personnel.

A flexible barrier 277, preferably comprised of several flaps 278, isdisposed within central opening 254, thereby substantially closing offthe central opening and preventing dilution of exhaled breath by ambientair during sampling. An opening 280 is preferably maintained withinflexible barrier 277, thereby ensuring a small part of central opening254 remains open in order to enable the subject to inhale external air.The flexible barrier 277 ensures that a majority of the subject's orallyexhaled breath will be directed toward oral prong 222 (FIGS. 11A and11B) thereby ensuring accurate sampling of the subject's breath. Opening280 is preferably placed at a top part of central opening 254 near thecut-away tip 224 of oral prong 222 (FIGS. 11A and 11B), therebydirecting and amplifying exhaled breath toward the oral prong 222 as itis the only substantial exit.

The flaps 278 are preferably formed of a plastic material selected to beof suitable thickness to maintain their position when undisturbed, yetbend readily when pushed by an endoscope probe, and thus do not limitthe actions of the medical personnel performing the endoscopy. However,the flaps 278 preferably close back around the endoscope probe, thusmaintaining a substantially closed oral cavity volume, and allowing mostof the exchange of gases to occur close to the opening 280 of flexiblebarrier 277, which opening is close to the cut-away tip 224 of oralprong 222 (FIGS. 11A and 11B) from which capnographic sampling can beperformed accurately.

Additionally, the flaps 278 are preferably transparent, thus enablingmedical personnel to see into the oral cavity during the endoscopyprocedure.

Two attachment surfaces 282, each formed with a slit 284, extendhorizontally outwardly from main body portion 252. Slits 284 are adaptedto connect to a band which is placed around the subject's head and isused to maintain the endoscopic bite block 250 firmly in position duringthe endoscopy procedure. Preferably, slits 284 are located above ahorizontal centerline of main body portion 252, such that the connectedband will tend to exert a stronger pull to the top of the main bodyportion 252, thus assisting in overcoming the subject's tendency to tiltthe bite block 250 outward during the endoscopy procedure and inmaintaining the bite block 250 upright in the subject's mouth.

Reference is now made to FIG. 14, which is a simplified schematicillustration of the connection between the oral nasal sampling cannulaof FIGS. 11A and 11B and the endoscopic bite block of FIGS. 12A-13.

As seen in FIG. 14, oral prong 222 of oral nasal sampling cannula 210 isaccommodated within groove 272 of bite block 250, such that a bottomsurface of oral breath directing element 226 engages transverse surface273 of the groove 272. It is appreciated that transverse surface 273 islocated below an inner surface of tubular portion 256 in order to ensurethat air exhaled by the subject into tubular portion 256 will bedirected toward groove 272 and oral prong 222.

Additionally, tip 276 of oral oxygen delivery tube 275 engages valve 244(FIGS. 11A and 11B) of T-element 240 of oral nasal sampling cannula 210,thereby opening the valve 244 and forming a fluid flow engagementbetween oxygen delivery tube 238 and tubular portion 274 of endoscopicbite block 250, which is in fluid flow engagement with the oral cavityof the subject.

Reference is now made to FIGS. 15A, 15B, 15C, 15D, 15E, 15F and 15G,which are pictorial illustrations of various stages of typical use ofthe endoscopic bite block assembly of FIGS. 11A-14.

As seen in FIG. 15A, the nasal prongs 218 of the oral nasal samplingcannula 210 are placed in the subjects nostrils, preferably before thesubject is sedated. Preferably, the exhaled breath collection tube 234and the oxygen delivery tube 238 are placed around the subject's ears,in order to ensure the stability of the oral nasal sampling cannula 210on the subject's face. As seen in the enlarged portion of FIG. 15A, atthis stage the oral breath-directing element 226 is in its retractedorientation, indicated by the length H3.

At this stage, oral oxygen delivery tube 275 (FIGS. 12A-13) is notconnected to the T-element 240 of oral nasal sampling cannula 210.However, even if oxygen is supplied to oral nasal sampling cannula 210via oxygen delivery tube 238, there is no oxygen leakage, as theT-element 240 is sealed by valve 244.

Turning to FIG. 15B it is seen that the oral breath directing element226 is extended to accommodate the facial dimensions of the subject,revealing part of oral prong 222. Preferably, the oral breath-directingelement 226 is moved down to a point in which a bottom end thereof is atthe height of the top of the bottom lip of the subject, its new lengthbeing indicated by H4. This action is preferably preformed by medicalpersonnel, but may alternatively be performed by the subject himself, afamily member, or any other person.

FIG. 15C illustrates the insertion of bite block 250 into the mouth ofthe subject, such that main body portion 252 engages the outer surfaceof the subject's lips and the tubular portion 256 is inside thesubject's mouth. Additionally, tip 276 of oral oxygen delivery tube 275is inserted, preferably by medical personnel, into valve 244 ofT-element 240 of oral nasal sampling cannula 210, as indicated by anarrow in the enlarged portion of FIG. 15C, thereby opening the valve244.

A strap, indicated by reference numeral 290, is attached to slits 284 ofattachment surfaces 282 and is placed around the subject's head, therebysecuring the bite block 250 in place. This stage is preferably performedwhen the subject is sedated, but may alternatively be performed priorthereto.

Turning to FIG. 15D, it is seen that air exhaled orally by the subject,indicated by arrows, passes through the bore of tubular portion 256, andis directed toward oral breath directing element 226 and oral prong 222by the flaps 278 of flexible barrier 277. Air that is exhaled nasally bythe subject passes through nasal prongs 218.

FIG. 15D illustrates the oral breath directing element 226 and the oralprong 222 being accommodated in groove 272, such that a bottom surfaceof the oral breath directing element 226 engages transverse surface 273of groove 272. Additionally, if oral breath directing element 226 hasbeen extended more than necessary for the facial features of thesubject, the transverse surface 273 pushes the oral breath-directingelement 226 back until it is optimally positioned. The lips of thesubject, indicated by reference numeral 292 preferably engage jawengagement recesses 264, and the top and bottom teeth of the subject,indicated by reference numerals 294 and 296 engage top and bottom teethengagement surfaces 260 and 262, respectively.

FIG. 15E illustrates the sedated subject, having the nasal prongs 218 ofthe oral nasal sampling cannula 210 in his nostrils and the endoscopicbite block 250 placed in his mouth and strapped to his head. Preferably,once the subject is sedated, oxygen is supplied to the nose of thesubject via oxygen delivery openings 236 of oral nasal sampling cannula210, and to the mouth of the subject via oral oxygen delivery tube 275and tubular portion 274, as indicated by arrows. The oxygen is suppliedto the oxygen delivery openings 236 via oxygen delivery bore 216 (FIGS.11A and 11B) and to oral oxygen delivery tube 275 via oxygen deliverytube 238 and T-element 240.

Turning to FIG. 15F, it is seen that when the subject is sedated, hetends to move or slump his head, thereby moving oral nasal samplingcannula 210 relative to bite block 250, as indicated by angle α in theenlarged portion of FIG. 15F. The feature of the present invention whichprovides oral nasal sampling cannula 210 which is physically separatedfrom bite block 250 and the placement of oral breath directing element226 and oral prong 222 within groove 272, ensure that even when thesubject moves or slumps his head, the oral prong 222 and nasal prongs218 will be maintained in their respective places, and accurate samplingwill continue. Additionally, the placement of oral prong 222 withingroove 272 provides a counter force to force applied by the subject'stongue to push at least the top portion of the bite block 250 out of thesubject's mouth, thus ensuring accurate placement of the bite block.

As seen in FIG. 15G, an endoscope probe 298 is inserted into the bore oftubular portion 256 of bite block 250, for performing the endoscopyprocedure. During the insertion of endoscope probe 298 and its presencein the subject's mouth and pharynx, flaps 278 of flexible barrier 277bend slightly inward to allow the passage of the endoscope probe 298, asseen with particular clarity in the enlarged portion of FIG. 150.However, the central opening 254 of bite block 250 remains substantiallyclosed by flaps 278, thereby separating the exhaled breath of thesubject which is in the bore of tubular portion 256 from the ambientair.

Additionally, the sampling may continue during the presence of theendoscope probe 298 in the pharynx of the subject, as the tubularportion 256 is of a slightly larger diameter than the central opening254, thereby ensuring that medical personnel have the space defined bythe difference between heights H2 and H1 (FIG. 13), as indicated byarrows in the enlarged portion of FIG. 15G.

It is appreciated that following the endoscopy the bite block 250 may beremoved from the subject's mouth, preferably by medical personnel. Priorto this stage, the tip 276 of oral oxygen delivery tube 275 is removedfrom valve 244 (FIGS. 11A and 11B) of T-element 240, thereby closing thevalve and fully decoupling the oral nasal sampling cannula 210 from theendoscopic bite block 250. However, the sampling of exhaled breaththrough nasal prongs 218 which remain in the subject's nostrils andthrough oral prong 222 which remains near the subject's mouth,preferably continues until the subject has awaken from the sedation.This is necessary because the subject's breath must be monitored as longas the subject is sedated.

It is appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of various featuresdescribed hereinabove as well as variations and modifications theretowhich would occur to a person of skill in the art upon reading the abovedescription and which are not in the prior art.

1-28. (canceled)
 29. A bite block comprising: a first hollow tubularportion configured for insertion into a subject's mouth, said firsthollow tubular portion comprising, on an outer portion thereof, a secondtubular portion configured to engage an oxygen supply tube, such thatwhen said oxygen supply tube is connected to said second tubular portiona valve is configured to open, and when said oxygen supply tube isdisconnected from said second tubular portion the valve is configured toclose; and a main body portion from which said first hollow tubularportion extends, said main body portion comprising a longitudinalgroove; wherein oral breath, exhaled through said first hollow tubularportion, is directed towards said groove.
 30. The bite block accordingto claim 29, wherein said valve comprises a normally closed valve. 31.The bite block according to claim 30, wherein said normally closed valvecomprises a luer valve.
 32. The bite block according to claim 31,wherein a mating luer portion of said luer valve is mounted onto abranch of said oxygen supply tube.
 33. The bite block according to claim29, wherein when said valve is open a majority of the oxygen is directedto an oral cavity of the subject.
 34. The bite block according to claim29, wherein when said valve is closed oxygen flow is directed to an oralnasal cannula.
 35. The bite block according to claim 29, wherein saidvalve is configured to be accommodated into said second tubular portion.36. The bite block according to claim 29, wherein said bite blockfurther comprises a flexible barrier closing off the first hollowtubular portion while leaving an opening near said oral prong, such thata majority of the exhaled oral breath is directed towards said oralprong.
 37. The bite block according to claim 36, wherein said flexiblebarrier comprises multiple flaps.
 38. The bite block assembly to claim37, wherein said flaps are transparent, to enable observation of theoral cavity of the subject during the endoscopic procedure.
 39. The biteblock according to claim 29, wherein an outer surface of said firsthollow tubular portion comprises top and bottom teeth engagementsurfaces, to facilitate accurate biting of said bite block by thesubject.
 40. An oral-nasal cannula comprising a main body portioncomprising: a breath collection bore and and oxygen delivery bore; twonasal prongs formed integrally with said main body portion, an oralprong mounted on a a bottom surface of said main body portion, whereinsaid two nasal prongs, said oral prong and said breath collection boreare in fluid flow communication; and a tube portion configured forconnection to a tube element of a bite, said tube portion comprising anormally closed valve, wherein said valve is configured to open whensaid tube portion is connection to said tube element of said bite block.41. The oral-nasal cannula according to claim 40, further comprising anoral breath directing element.
 42. The oral-nasal cannula according toclaim 41, wherein said oral breath directing element is slidably mountedonto said oral prong.
 43. The oral-nasal cannula according to claim 41,wherein said oral breath directing element is configured to retract andextend.
 44. The oral-nasal cannula according to claim 40, wherein saidmain body portion further comprises a plurality of oxygen deliveryopenings, said oxygen delivery openings being in fluid flowcommunication with said oxygen delivery bore.
 45. A bite blockcomprising: a first hollow channel configured for insertion into asubject's mouth, said first hollow channel comprising a second channel;and a main body portion from which said first hollow channel extends,said main body portion comprising a tube element configured todetachably connect to an oral-nasal cannula, such that when saidoral-nasal cannula is connected to said tube element a valve isconfigured to open, and when said oral-nasal cannula is disconnectedfrom said tube element the valve is configured to close.